Cisco NX-OS supports Intrusion Detection System (IDS) checks that validate IP packets to ensure proper formatting. This is an enhancement beginning in 5.x. The EEM message is being logged because a packet is received by the switch where the Ethernet frame size is shorter than the expected length to include the IP packet length plus the Ethernet header. The packet is dropped by the hardware due to this condition.
In order to verify that the IDS drops occurred since the last switch reboot, issue the show hardware forwarding ip verify module [#]”.